This grant supports the study of abnormal physiologic conditions and comparative diseases that are of interest in biomedical research. Particular emphasis is placed on environmental variables affecting research data. BIBLIOGRAPHIC REFERENCES: White, W. J., Kopp, D., and Lang, C. M. Age related changes in glycoside hydrolase activities in postweaning hamsters. Comp. Biochem. Physiol, 54:397-400, 1976. Hughes, Howard C., Jr., White, William J., and Lang, C. Max, Guidelines for the use of tranquilizers, anesthetics, and analgesics in laboratory animals. Vet. Anes. 11:19-24, 1975 (published in 1976).